White and red emitting LaF3 nanocrystals doped with Eu2+ and Eu3+ ions: Spectroscopic and magnetic studies

LaF3:Eu3+ nanoparticles were synthesized by a co-precipitation method using glycerine or Triton X-100 as a surfactant. Structure and morphology of the nanocrystals were characterized on the basis of X-ray diffraction and transmission electron microscopy. The average crystallite size was calculated from the full-width at half-maximum of the diffraction peaks using the Scherrer equation. The nanopowders obtained were composed of nanocrystallites with the average size 9 +/- 1 nm and 13 +/- 2 nm for LaF3:5% Eu3+ prepared using glycerine or Triton X-100, respectively. An interesting result was, that using glycerine provided partial reduction of the Eu3+ to Eu2+ and hence white luminescence under UV excitation. The luminescent properties of the nanoparticles were investigated by excitation and emission spectra. Luminescence lifetimes were analyzed and discussed and the chromaticity coordinates were calculated. The magnetic analysis of the nanophosphors obtained was conducted in order to observe the influence of the Eu2+ ions on the magnetic properties of the samples prepared. The magnetic properties of lanthanum fluorides depend on the parameters of those rare earth elements and the substitutions. (C) 2016 Elsevier B.V. All rights reserved.